VI.] THEIR SIGNIFICANCE IN HEREDITY. 359 



July, 1886, 1 published a short note^ on part of the observations 

 made upon parthenogenetic eggs, I confined mj^self to facts, 

 and did not mention this conclusion. I took this course simply 

 because I did not wish to bring it forward until I had made 

 sufficient observations in the first of the two ways described 

 above. I had hoped to be able to offer all the proofs that can 

 be obtained before undertaking to publish the far-reaching 

 consequences which would result from the above-mentioned 

 conclusion. Unfortunately the material with which I had 

 hoped to quickly settle the matter, proved less favourable 

 than I had expected. Many hundred sections through freshly 

 laid winter-eggs of Bythotrephes longiiuanus were made in vain ; 

 they did not yield the wished-for evidence, and although con- 

 tinued investigation of other material has led to better results, 

 the proofs are not yet entirely complete. 



I should not therefore even now have brought forward the 

 above-mentioned conclusion, if another observer had not alluded 

 to this idea, referring to my observations and also to a new dis- 

 covery of his own. In a recent number of the ' Biologische 

 Centralblatt,' Blochmann ^ gives an account of his continued 

 observations upon the formation of polar bodies. It is well 

 known that this careful observer had previously shown that 

 polar bodies do occur in the eggs of insects, although they had 

 not been found before. Blochmann proved that they are found 

 in the representatives of three different orders, so that we may 

 indeed 'confidently hope to find corresponding phenomena in 

 other insects.' This discovery is most important, and it was 

 naturally very welcome to me, as I had for a long time ascribed 

 a high physiological importance to the process of the formation 

 of polar bodies, and it would not be in accordance with such 

 a view if the process was entirely wanting from whole classes 

 of animals. To fill up this gap in our knowledge, and to give 

 the required support to my theoretical views, I had proposed 

 to one of my pupils, Dr. Stuhlmann'% that he should work out 



^ Weismann, ' RichtungskOrper bei parthenogenetischen Eiern,' Zool. 

 Anzeiger, 1886, p. 570. 



■^ Blochmann, ' Ucbcr die Richtungskorper bei den Insckteneiern,' 

 Biolog. Centralblatt, April 15, 1887. 



^ F. Stuhlmann, ' Die Reifung des Arthropodeneies nach Beobach- 

 tungen an Insekten, Spinnen, Myriapoden und Peripatus,' Berichte der 

 Naturforschenden Gesellschaft zu Freiburg i. Br., Bd. I. p. loi. 



